The present invention relates generally to an electronic lock system for operating a lock mechanism with an input code entered from a pushbutton keyboard. The invention especially relates to an electronic lock mechanism with an audible entry monitor which produces an audible signal each time one of the push buttons is operated.
Such an electronic lock system is applicable for an automotive door lock system. A typical automotive door lock system is disclosed in U.S. Pat. No. 4,205,325, issued on May 27, 1980 to Haygood et al which shows a keyless entry system for locking and unlocking a vehicle door lock mechanism. In Haygood et al, several functions are incorporated in a single keyless entry system for an automotive vehicle. Major improved features include a permanent preprogrammed code storage memory and a user programmable code storage memory, wherein either code may be inserted into the system to gain entry into the vehicle and enable the other functions. The other functions include the ability to unlock one or several doors of the vehicle, retract a sunroof, unlock a deck lid, lower selected side windows, reprogram a new user selected code into the programmable memory or disable the system response to the user selected code. These functions have been found to be highly desirable since they can be controlled to occur prior to entering the vehicle.
Five digit designated pushbutton keyboards on opposite vehicle doors are provided in the preferred embodiment, as the means by which all predetermined codes are manually entered into the system. A primary keyboard mounted on the left front (driver's) door is designated by the system to have continual override priority over the keyboard mounted on the right front (passenger's) door. However, each keyboard has independent operational capability to allow a user to enter correct digit codes and have the system perform the aforementined functions.
In operation of Haygood et al, depression of any pushbutton on either keyboard will cause illumination of the keyboard, activation of the system, and may also cause illumination of the vehicle interior for a predetermined period of time. In this manner, the system becomes visible for night operation and is activated to receive a multi-digit code which corresponds to either the permanent preprogrammed code or a programmed user selected code. The user then depresses a sequence of digitally designated pushbutton and each depression commences a new time period for illumination and activation. In order to eliminate excessive battery drain, the system will deactivate and illumination will terminate if the user hesitates longer than the predetermined time period. When proper entry of either the permanent or user selected multi-digit code is completed, the door upon which the particular keyboard is mounted will immediately unlock and allow entry to the passenger compartment of the vehicle. Subsequently, while the system remains activated during the aforementioned time period, predetermined digital pushbuttons may be depressed to unlock all the other vehicle doors, unlock the deck lid, retract the sunroof, lower the side windows, program a new user-selected code into the programmable memory, or disable the system response to the last programmed user-selected code.
In the particular point of the present invention, the keyless entry system can be operated via either of two different present codes. One of the preset codes is a permanent code which can also be used to allow reselection of the other preset code. The other code is a voluntary code or user's code and is the one normally used for door unlocking. The system permits change of the voluntary code when the newly desired voluntary code is inputted following the permanent code.
The system includes an audible entry monitor for confirmation of inputs. The entry monitor is adapted to produce an audible entry confirmation tone every time one of the push buttons is depressed. The entry monitor produces another audible signal when the system is ready to change the voluntary preset code for a given period of time during which the system will accept entry and change of the voluntary code.
In addition, the system has a mischief preventive circuit for preventing the electronic lock system from being mischiefed.